Threadless spark plug and adapter therefor



H. MUNROE THREADLESS SPRK PLUG AND ADAPTER THEREFOR June 2k, 1925.

Filed July 25. 1923 Patented J une Z, 1925.

UNITED STATES 'HARRY MUNRO'E, 0E NEW YORK, N. Y.

THREADLESS SPARK PLUG AND ADAYTER THEREFOB.

Application led July 25, 1923. Serial No. 653,733.

To all lwhom it' may concern:

Be it known that I, HARRY MUNROE, a citizen of the United States, residing at New York city, in the county of New York and State of New York, have invented certain new and useful Improvements in Threadless Spark Plugs and Adapters Therefor, of which the following is a speciiication. p

This invention relates to spark plugs for internal combustion engines.

One object of the present invention is to provide a spark plug for internal combustion engines which can be easily and quickly inserted into and .removed from its position in the internal combustion engine.

Another object is to provide such a spark plug with improved retaining means therefor in which the necessity of providing screw threads on the spark plug proper is eliminated and which has a gas tight fit within the internal combustion engine.

A further object is to provide a spark plug in combination with an adapter therefor, which will allow easy insertion and removal of the spark plug for cleaning or repairs in spite yof expansion and contraction of parts due to increase and decrease of temperature.

A still further object is to provide a spark plug of the character described which shall be simple in construction, relatively inexpensive, and which can be readily applied to internal combustion engines now -in use.

An embodiment of invention is illustrated by way of example in the accompanying drawings, in which- `Figure 1 is a perspective view of the detached parts of the adapter,

Fig. 2 is a perspective view of the detached parts of a slightly modified form of adapter, f Fig. 3 is 4a side elevation, partly in section, of the spark plug proper and,

Fig. 4 is a vertical sectional view through the assembled device.

Referring to Fig. 1, the adapter here shown comprises a substantially cylindrical hollow body portion 1, having a shoulder 2, forming a ground seat near the reduced and exteriorly screw threaded lower end 3 by means of which the adapter may be attached to any of the ordinary forms of internal combustion engines. The shoulder 2 is illustrated as being arranged at an angle of substantially 45 to the axis of the cylindrical body portion 1, for convenience in the assembly and dis-assembly of the spark plug proper within the adapter,

though it is obvious that the angle may be either greater or less than 45 without departing from the spirit of the present invention. The purpose of the shoulder 2 is to provide a ground seat as a part of the adapter, and which acts in conjunction with the gaskets presently to be described, to form a gas tight fit. f

The upper end of the adapter is provided with a circumferentially extending flange or shoulder 4. The shoulder 4. is formed with a polygonal outer edge, here shown in the form of a hexagon, in order that it may be more readily engaged by a wrench or other tool for screwing the adapter into and out of its position in the internal combustion engine.

The cylindrical portion 1 extends above epd beyond the shoulder 4, and is exteriorly screw threaded for engagement with a coupling member. Portions of this threaded extension are removed at diametrically opposite points to facilitate removal of the spark plug proper from the adapter, leaving two opposed and spaced exteriorly screw threaded projections 5, around which the coupling or cap member 6 is adapted to fit in screw threaded engagement.4 j S The coupling member 6 is inthe form of a capI having downwardly extending spaced exteriorly screw threaded projections 7 ,'by means of which the coupling is screwed upon the main body portion of the adapter over the screw threaded projections 5.

Extending radially from the coupling or cap member 6v are two wing portions 8, to facilitate manually screwing or unscrewing the coupling member from the body por.- tion of the adapter. The interior of the coup-ling or cap 6 is hollow to enclose and protect the top portion of the spark plug' proper, and the top of the coupling is illustrated as being spherical, though it could as well be formed fiat or in any# other shape desired. j,

The coupling or cap 6 has an opening 9 extending radially therethrough, to provide access to the end of the spark plug proper without removing the coupling. The opening 9 is shown as being arranged between the wing. portions 8 and above the screw threaded projections. 7. Within the hollow portion of the coupling capl 6 are two downwardly facing oppositely arranged shoulder portions 10, one on either side of the opening 9. These shoulders 10 are adapted to engage a washer or gasket provided on thc spark plug proper for the purpose of holding said spark plug in place within the adapter' and in gas tight relation thereto.

In order to prevent accidental displacement or unscrewing lof the cap 6 from the body portion of theadapter, a catch or fastening means is provided which will now be described. A series of grooves 1l is provided on the projections 5, said grooves running substantially at right angles to the. direct-ion of the screw threads. Formed in one or both of the projections 7 is a slot 12, which passes successively over each of the grooves 11 as the coupling 6 is screwed into place. A catch or locking member is adapted to project through the slot 12 and into one of the grooves 11 for.holding the coupling 6 in place.

This catch or locking member may take i the form of a substantially flat spring 13, one end-of which is pivotally attached to the outside of one of the projections 7 and the other end of which is bent inwardly at right angles, to extend through the slot 12 and into one of the grooves 11. lVhen it is desired to screw or unscre-W the coupling 6 the bent end of the spring 13 can be removed from the slot 12 and the spring swung about its pivot until the bent end lies above or below the slot. When the coupling is to be locked in position, it is only necessary to swing the spring about its pivot until the bent end drops into the slot .12, where the sprin pressure will hold it and force it into the rst groove it meets, thereby preventing accidental displacement or removal of the coupling.

Referring to Fig. 2, the modification here disclosed is substantially the same as the construction f above described, except that the exteriorly screw threaded end 5a of the adapter body is continuous, and the screw threaded lower end (7) of the coupling 6 is continuous. The same locking means may be used as before.

Referring to Fig. 3, the spark plug here shown comprises an insulator consisting of a porcelain body 14, in which is disposed a centre electrode 15, which may be molded in the porcelain to Y prevent its removal therefrom. The porcelain body is provided with shoulders 16 and 17 near its reduced ends 18 and 19 respectively. The centre electrode 15 projects beyond the end 18 of the porcelain body, and is screw threaded at said' projecting end for engagement with the usual knurled thumb nuts 20 for holding the lead terminal from the sparking system in the usual manner. The thumb nuts 20 are spaced from the porcelain body by a outer electrode of the plug,

washer 21, which may be composed of libre or bakelite, and which has a diameter of a size to enable it to tit conveniently within the coupling 6.

The shoulder 16 is provided with copper and asbestos gaskets 22 for contact with the shoulders 10 of the coupling 6. Similarly, the shoulder 17 is provided with copper and asbestos gaskets 23 for engagement with the tapered portion 24 of the outer shell or receptacle 25, into which the porcelain body 14 is inserted.

The reference numeral 27 designates the which is secured to the lower end of the shell or container 25 in any suitable manner, and has a right angularly bent end arranged in proximity to the end 28 of the centre electrode 15, the arangement being such that sparks will pass between the ends of the electrodes in thel usual manner when the plug is 1n use.

In using the improved threadless spark plug and adapter herein described, the adapter 1 is screwed into position in the internal combustion engine until the ground seat 2 abuts the adjacent part of said engine. The spark plug shown in Fig. 3 is then inserted within the adapter 1 into which it fits easil for removal in spite of expansion, and t e coupling or ca 6 is screwed into place until the shoul ers 10 abut the gaskets 22, in which position it is held from accidental rotation by the spring catch 12. The gaskets rovided form gas tight joints, and allow or expansion contraction of parts due to changes of temperature.

It will be seen that a construction is thus provided which is secure and gas tight, which has a spark plug that is easily removable for cleaning or repairs, and upon which it has not been necessary to provide screw threads for securing it in place. The

only screw threads used are those upon the.

adapter, which need not be removed once it is screwed int-o place, and the spark plugs thereafter used need not be put through any screw threading operation.

It will be understood that` the terms u per and lower as used herein refer to t e position of parts illustrated in the drawings, and that the invention itself may be used in any position.`

I claim:

1. In a device of the character described, an adapter having a circumferential flange,

Aspaced screw threaded projections extendlng above said flange, a threadless s ark plug arranged within said adapter and aving one end projecting therefrom, a coupling or cap member adapted to enclose said projecting end of the spark plug, downwardly extending, spaced, screw-threaded projections carried bv said cap member and adapted to engage the projections on said adapter, a gasket surroundin said spark plug, and shoulders carried y said cap member adapted to automatically engage said gasket When the cap member is secured in position to e'ect a gas-tight connection.

2. In a device of the character described,

an adapter having a circumferential flange,'

` spaced screw-threaded projections extending above said flange, a threadless spark plug arranged Within said adapter and having one end extending thereabove, a cap member adapted to enclose said end of the spark plug, spaced depending screw-threaded projections carried by said cap members and adapted to engage the projections on said adapter, a series of spaced slots arranged on the screw-threaded projections on the adapter, said slots being arranged at substantially right angles to the threads, one of' the depending flan es carried by the cap member being provi ed with a corresponding slot, and a spring catch pivotally mounted on said depending projection and adapted to enter the slots and lock the cap to the adapter.

In testimony whereof I affix my signature.

HARRY MUN ROE. 

